On 12/10/10 14:08, Daniel P. Berrange wrote:
On Tue, Oct 12, 2010 at 02:05:25PM +0100, Matthew Booth wrote:
> remap_block_devices was modifying the global device list while remapping device
> names for libata guests (which includes RHEL 6). This caused a failure later
> when the renamed devices were not present in the original XML.
>
> Fixes RHBZ#641869
> ---
> lib/Sys/VirtV2V/GuestOS/RedHat.pm | 14 +++++++++++++-
> 1 files changed, 13 insertions(+), 1 deletions(-)
>
> diff --git a/lib/Sys/VirtV2V/GuestOS/RedHat.pm b/lib/Sys/VirtV2V/GuestOS/RedHat.pm
> index a322a5d..cc95fd8 100644
> --- a/lib/Sys/VirtV2V/GuestOS/RedHat.pm
> +++ b/lib/Sys/VirtV2V/GuestOS/RedHat.pm
> @@ -1567,7 +1567,19 @@ sub remap_block_devices
> $letter++;
> }
>
> - map { $_ = $map{$_} } @$devices;
> + # N.B. Don't use map() here because we mustn't modify the
original
> + # devices list
The problem isn't that you used map(), it is that your map code block
has side effects. You should be able to avoid the side effect thus:
my @newdevices = map { $map{$_} } @$devices;
Thanks, Dan.
As it turns out I'm going to leave the loop as is because it contains an
additional sanity check which spoils the conciseness of map(). With the
extra test, I think this form is cleaner. I have, however, updated the
comment to not blame map :)
Matt
--
Matthew Booth, RHCA, RHCSS
Red Hat Engineering, Virtualisation Team
GPG ID: D33C3490
GPG FPR: 3733 612D 2D05 5458 8A8A 1600 3441 EA19 D33C 3490